Recently, needs for motor controlling devices, which are mounted on vehicles and used in EPS systems (Electric Power Steering systems), electric braking systems, etc., have rapidly been increased with a shift to electric operations of actuators mounted on automobiles. Because an electric actuators is substituted for the conventional hydraulic actuator, a very fast control response is demanded and a DC brushless motor (DCBL motor) is used in the motor controlling device for mounting on the vehicle. In order to satisfy the demand for such a fast control response, JP,A 2001-315657, for example, discloses one known technique of constituting a disturbance voltage observer to realize high-response torque control. Also, JP,A 4-340390, for example, discloses another known technique of constituting a current control calculation section for 120°-energization with separate hardware.